SPECIAL UPDATE…TROPICAL DISTURBANCE INVEST 97L FORECAST SYNOPSIS…SEP. 01, 2013…ISSUED 7:30 P.M. EDT…PHFC

Good evening everyone!

Tropical Disturbance INVEST 97L continues to become somewhat better organized, especially during the last few hours.  There has been quite an increase in convection over the past 24 hours.  Based on the 1800Z update of ATCF FTP data, and satellite loop imagery, the following data was available on INVEST 97L, and is plotted on the Global Tracks 7 Tracking map:

GT7 INVEST 97L TRACKING MAP
INVEST 97L

Analysis of IR2 Shortwave satellite imagery loops indicate the convection is now just on the eastern edge of this LLC, and the satellite appearance may suggest a center reformation could be occurring under the convection, and notable in the low level winds based on low level steering with satellite overlay.  The NHC has designated a MEDIUM (40%) chance of this INVEST becoming a tropical cyclone during the next 48 hours.

INVEST 97L SATELLITE LOOP IMAGERY

INVEST 97L SHORTWAVE IR2

CARIBBEAN WATER VAPOR LOOP

NHC GRAPHICAL TROPICAL WEATHER OUTLOOK

LOW LEVEL STEERING

The current wind shear map from CIMSS indicates upper level conditions are not as favorable as a few hours ago, when an upper level anticyclone was established over the system, however the upper level wind pattern does indicate an outflow jet north and south
of the center of the convection.

CIMSS WIND SHEAR 

UPPER LEVEL WINDS

The most recent run of the GFS wind shear forecast indicates upper level winds should become very favorable for further development in about 2-3 days, and could be over INVEST 97L should it track based on the current forecast steering layers maps.

GFS WIND SHEAR FORECAST 72  HOURS FROM 12Z

Water Vapor satellite loop imagery does indicate dry air directly north of the disturbance, however, INVEST 97L will be entering an area of higher TCHP once it crosses the Lesser Antilles.  This may be enough heat energy to allow 97L to moisten the atmosphere around it enough to survive.

TCHP

Based on these analysis parameters, I feel 97L will continue to become slowly organized, and could potentially organize at a more steady rate once in the central and western Caribbean areas.

The 18Z run of the Dynamic Model Guidance only displayed one model, which has 97L heading off to the NW in a couple of days.  Based on the steering layers forecast at the moment, I must discount this, as steering suggest a motion toward the WSW in about 48 hours or so, then back toward the west thereafter.

Two things we will need to monitor on this, the strength of this system, and whether or not the steering follows the GFS forecast currently, or the CMC.  SHOULD there not be any changes, the GFS steering suggests a continued west to WNW near the end of the period, and this could affect somewhere near Nicaragua or Honduras.  The CMC solution places it in a position where there could be a possible U.S. threat.  Two longwave trofs are forecast to move north of the system, and depending on how strong these may be, and the strength of the system, will determine which model right now shows the best solution.  However, BEAR IN MIND…steering goes out to 6 days, so this is just an estimate based on just this one run.  Steering factors can change in a matter of 24 hours…so at the moment, this is more of a message to keep this in the back of your mind.

I will have another update in the a.m. sometime.

Have a blessed evening!

T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST
MEMBER WEST CENTRAL FL AMS
CERTIFIED SKYWARN OFFICIAL STORM SPOTTER (advanced)
CoCoRaHS OBSERVER

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About palmharborforecastcenter

I am a Tropical Forecast meteorologist, providing hurricane forecasts during the Atlantic Hurricane Season. I retired from the U.S. Coast Guard in July of 2001. Meteorology became my passion in high school, and I have continued my educational background in meteorology since 1996, when I undertook the study of Tropical Meteorology. While working toward my degree, I had to unexpectedly withdraw from college due to my oldest sons medical reasons. I do however, meet the educational criteria of the AMS to be recognized as a meteorologist. Studies include, but are not limited to the Navy Aerographers Mate course, Naval METOC meteorology course, Meteorology 2010 Sophomore level course while attending St. Petersburg College, Clearwater, FL., Basic Forecasting course for operational meteorologists from Rapid WX, meteorology institute, a four month meteorological internship, and extensive research on numerous meteorological topics such as the MJO, NAO, satellite imagery interpretation, etc. I have been forecasting Tropical Weather (Tropical Storms and Hurricanes) since 1996, with my main client being three different Coast Guard Commands.
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17 Responses to SPECIAL UPDATE…TROPICAL DISTURBANCE INVEST 97L FORECAST SYNOPSIS…SEP. 01, 2013…ISSUED 7:30 P.M. EDT…PHFC

  1. Beachgirl says:

    Thanks Storm!!

  2. originallt says:

    Thanks for posting on this Labor Day weekend. At about 10:15pm this evening, the convection doesn’t look as good as it did earlier, but I know it could easily flair back up again.

  3. Mike Doll says:

    Thanks Storm!!!!!

  4. stefanie says:

    Thanks Storm. Appreciate the weekend time. 🙂

  5. Greg goodman says:

    Sorry you had to work on labor day Mr storm could this get into the gulf.

  6. Monty says:

    Thanks as always Storm…figured you would throw something out on your day off. Here we go…NHC says something might be brewing in Bay of Campeche in a few days?? Do you think the dry air will play a role in 97L? Boy…glad to have you around Storm!!

  7. TexasHurricane says:

    Thanks storm! Wasn’t sure if you were going to post or not this Labor Day weekend. Have a great evening. 🙂

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